Cricothyrotomy (also called Cricothyroidotomy) is a life-saving procedure to create an alternative airway in emergency situations. The cricothyroid membrane is a useful place to access the airway in the case of glottis and subglottic obstruction, injury, facial muscles spams or laryngospasm, uncontrollable emesis, upper airway stenosis or congenital deformities, clenched teeth, tumor, cancer and nose bleeding. Locating the cricothyroid membrane (CTM) during a cricothyrotomy procedure can prove challenging especially in the case of obese patients, women and children due to the difficulty in isolating anatomical landmarks. Currently, this procedure is contraindicated for children younger than 12 years old due to their smaller cricothyroid membrane and a more funnel-shaped, rostral and compliant larynx.
Cricothyrotomy is restricted to experienced or high level EMT's, paramedics, anesthesiologists and emergency physicians. Cricothyrotomy is an emergency procedure, which usually lasts <1 minute. Detection itself can last from 15 to up to 30 seconds.
The cricothyroid membrane (CTM) is small and surrounded by adjacent structures—including the cricothyroid muscles, thyroid and cricoid cartilages, and central cricothyroid arteries. Damage to any of these surrounding structures accounts for up to 40% failure in practice and can lead to perichondritis, stenosis, subcutaneous emphysema, hemorrhage, pneumothorax, laceration of esophagus or trachea, and anoxia. Delayed complications include tracheomalacia, bleeding, infection, fistulae, displacement and scarring.
There are currently two approaches to detect the cricothyroid membrane. The first one is palpation, which is done by emergency medical technicians (EMTs), army medics and other first response services. Palpation is highly inaccurate and biased but is the most common used in the medical field. The second approach is ultrasound, which is done in the hospitals under controlled conditions. Ultrasound is expensive, slow to operate, relatively bulky, requires a specific probe for soft tissue and is rarely available in the field. The approximate cost of a 2D, Doppler and M mode ultrasound from Sonosite, such as MicroMaxx is >$1500.
The time factor is an aspect to be considered for detecting CTM, since this emergency health care procedure operates in the “golden hour”. If a device cannot detect CTM in a reasonable amount of time, there would be no practical use for it in the field. More importantly, in a patient that has been without oxygen for more than 5 minutes, it is unlikely that the patient will survive, and even if they do, there is a high possibility of brain damage. Thus, a device must be able to identify the cricothyroid membrane within a matter of seconds.
There is also a need for a device to detect other types of tissues. For example, X-ray is a traditional form to detect bone fractures. However, cartilage and tendons are difficult to visualize by X-rays in children.
Accordingly, there is a need for a rapid detection system to help health care providers detect underlying tissues in an accurate way, for example, in a cricothyrotomy procedure.